<template>
  <div class="drag" ref="dragDiv">
    <div class="drag_bg"></div>
    <div class="drag_text">{{confirmWords}}</div>
    <div ref="moveDiv" @touchstart="mousedownFn($event)" :class="{'handler_ok_bg':confirmSuccess}" class="handler handler_bg" style="position: absolute;top: 0px;left: 0px;"></div>
  </div>
</template>

<script>
export default {
  data () {
    return {
      beginClientX: 0, /* 距离屏幕左端距离 */
      mouseMoveStata: false, /* 触发拖动状态  判断 */
      maxwidth: '', /* 拖动最大宽度，依据滑块宽度算出来的 */
      confirmWords: '拖动滑块验证', /* 滑块文字 */
      confirmSuccess: false /* 验证成功判断 */
    }
  },
  methods: {
    mousedownFn: function (e) {
      if (!this.confirmSuccess) {
        e.preventDefault && e.preventDefault() // 阻止文字选中等 浏览器默认事件
        this.mouseMoveStata = true
        this.beginClientX = e.changedTouches[0].clientX
      }
    }, // mousedoen 事件
    successFunction () {
      this.confirmSuccess = true
      this.confirmWords = '验证通过'
      this.$emit('refreshDataList', true)
      if (window.addEventListener) {
        document.getElementsByTagName('html')[0].removeEventListener('touchmove', this.mouseMoveFn)
        document.getElementsByTagName('html')[0].removeEventListener('touchend', this.moseUpFn)
      } else {
        document.getElementsByTagName('html')[0].removeEventListener('touchend', () => {})
      }
      document.getElementsByClassName('drag_text')[0].style.color = '#fff'
      document.getElementsByClassName('handler')[0].style.left = this.maxwidth + 'px'
      document.getElementsByClassName('drag_bg')[0].style.width = this.maxwidth + 'px'
    }, // 验证成功函数
    mouseMoveFn (e) {
      if (this.mouseMoveStata) {
        let width = e.changedTouches[0].clientX - this.beginClientX
        if (width > 0 && width <= this.maxwidth) {
          document.getElementsByClassName('handler')[0].style.left = width + 'px'
          document.getElementsByClassName('drag_bg')[0].style.width = width + 'px'
        } else if (width > this.maxwidth) {
          this.successFunction()
        }
      }
    }, // mousemove事件
    moseUpFn (e) {
      this.mouseMoveStata = false
      let width = e.changedTouches[0].clientX - this.beginClientX
      if (width < this.maxwidth) {
        document.getElementsByClassName('handler')[0].style.left = 0 + 'px'
        document.getElementsByClassName('drag_bg')[0].style.width = 0 + 'px'
      }
    }, // mouseup事件
    setReset () {
      this.confirmSuccess = false
      this.confirmWords = '拖动滑块验证'
      document.getElementsByClassName('handler')[0].style.left = 0 + 'px'
      document.getElementsByClassName('drag_bg')[0].style.width = 0 + 'px'
      document.getElementsByTagName('html')[0].addEventListener('touchmove', this.mouseMoveFn)
      document.getElementsByTagName('html')[0].addEventListener('touchend', this.moseUpFn)
    }
  },
  mounted () {
    this.maxwidth = this.$refs.dragDiv.clientWidth - this.$refs.moveDiv.clientWidth
    document.getElementsByTagName('html')[0].addEventListener('touchmove', this.mouseMoveFn)
    document.getElementsByTagName('html')[0].addEventListener('touchend', this.moseUpFn)
  }
}
</script>

<style scoped>
  .drag{
    position: relative;
    background-color: #e8e8e8;
    width: 100%;
    height: 88px;
    line-height: 88px;
    text-align: center;
  }
  .handler{
    width: 90px;
    height: 88px;
    border: 1px solid #ccc;
    cursor: move;
  }
  .handler_bg{
    background: #fff url("") no-repeat center;
  }
  .handler_ok_bg{
    background: #fff url("") no-repeat center;
  }
  .drag_bg{
    background-color: #7ac23c;
    height: 88px;
    width: 0px;
  }
  .drag_text{
    position: absolute;
    top: 0px;
    width: 100%;
    text-align: center;
    font-size: 26px;
    color: #999999;
    -moz-user-select: none;
    -webkit-user-select: none;
    user-select: none;
    -o-user-select:none;
    -ms-user-select:none;
    background: -webkit-gradient(linear, left top, right top, color-stop(0, #4d4d4d), color-stop(.4, #4d4d4d), color-stop(.5, #fff), color-stop(.6, #4d4d4d), color-stop(1, #4d4d4d));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    -webkit-animation: lock 2.6s infinite;
    -webkit-text-size-adjust: none;
  }
  @-webkit-keyframes lock {
    0% {
      background-position: -140px 0;
    }
    100% {
      background-position: 140px 0;
    }
  }

  @keyframes lock {
    0% {
      background-position: -140px 0;
    }
    100% {
      background-position: 140px 0;
    }
  }
</style>
